However, since 1462, Casimir IV had had an alliance with George of Poděbrady, which caused Pope Pius II suspicion after the Thirteen Years' War, during which Poland fought against the Teutonic Order. In addition, the princess's mother Queen Elizabeth was also agains the match, stating that Matthias is a peasant, a midget, a Vlach, a dog, simply not worthy of her (pl: Matyasz chłop, kurczek, Wołoszyn, pies, niegodziem jej).[2] Despite this, Bishop Protas was chosen to be godfather at the baptism of the new son of King Casimir IV, born on 27 April 1467, who was named Frederick after the Emperor.

In 1469, the Catholic party of the Kingdom of Bohemia formally offered the crown to Matthias Corvinus. George of Poděbrady sought the support of Poland, promising the succession of the eldest son of Casimir IV, Vladislaus in exchange of their help. Corvinus, fearing this Polish-Bohemian alliance, again requested the hand of Hedwig, but was refused.

On 20 October 1470, Casimir IV and Frederick signed a treaty in the city of Graz, and a possible marriage between Hedwig and Maximilian was also discussed.

Matthias Corvinus asked the hand of Hedwig again in July 1471 and in September 1473 until finally, a definitive refusal was made by Queen Elizabeth. At the beginning of 1473, two counselors sent by Albert IV, Duke of Bavaria-Munich arrived in Poland with a marriage proposal; however, Casimir IV refused the offer because at that time, he was already negotiating a marriage between his eldest daughter and George, son and heir of Louis IX, Duke of Bavaria-Landshut.

Casimir IV, in order to protect his south-western borders with the Kingdom of Bohemia (subject to the rivalry between his son Vladislaus and Matthias Corvinus), decided to enter into a closer alliance with Bavaria. In 1473, the Polish deputies Stanisław Kurozwęcki and Paweł Jasieński were sent to the Landshut court to begin talks for a marriage between Hedwig and George. As a result, on 7 or 10 September 1474, Duke Louis IX of Bavaria-Landshut sent an official message asking Hedwig's hand for his son. Negotiations took place in the cities of Łęczyca and Radom, where on 30 December, Hedwig agreed to marry George. The next day, the marriage contract was signed. Hedwig received as a dowry to the amount of 32,000 Hungarian złoty, payable in 5 installments over the next five years. The cost of the trip of the Polish princess to her new home reached 100,000 złoty.

Due to the fact that the future spouses were closely related (Hedwig's maternal grandfather Albert V of Austria was a brother of George's paternal grandmother, Margaret of Austria), the Polish Royal Chancellor Uriel Górka travelled to Rome in 1475 to seek the required dispensation, which was granted by Pope Sixtus IV on 26 May of that year.

Hedwig arrived with her family in Poznań, where on 10 October 1475, she said goodbye to them. With a large retinue of approximately 1,200 knights, she arrived in Wittenberg on 23 October. She was accompanied, among others, by Anna, widow of Bolesław II, Duke of Cieszyn.

In 1479, Hedwig became Duchess-consort of Bavaria-Landshut after the death of her father-in-law. Her marriage was unsuccessful; her husband was a known alcoholic and womanizer. In 1485, George banished his wife from the Ducal court in Landshut and placed her in Burghausen Castle, where she lived with her own court and numerous servants, but – according to contemporary chroniclers — deprived of all the pleasures of the world and comforted only with her loneliness.[3] It is not known whether she was accompanied by her children in her exile.

Hedwig, who signed her letters as geborene Königin von Polen (Queen of Poland by birth), didn't maintain close contact with her family. On 31 January 1503, her brother, King Alexander of Poland, wrote to her husband that he hadn't known that Hedwig had died eleven months previously.

Hedwig, Duchess of Bavaria-Landshut, died unexpectedly on 18 February 1502 at Burghausen Castle. She was buried in the Cistercian monastery of Raitenhaslach near Burghausen. When the monastery was secularized in 1803, her tombstone was destroyed. However, there is a commemorative stone in the floor of the Church in the place where her grave was previously located.